<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        header,nav,section,aside,article,footer{
            border: 1px solid red;
        }
        header{
            height: 100px;
        }
        nav{
            height: 40px;
        }
        section{
            height: 300px;
            position: relative;
           
        }
        aside{
            width: 25%;
            height: 300px;
            position: absolute;
            left: 0;
            top: 0;
        }
        article{
            width: 73%;
            height: 300px;
            position: absolute;
            left: 26%;
            top: 0;
        }
    </style>
</head>
<body>
    <header>头部</header>
    <nav>导航栏</nav>
    <section>
        <aside>侧边栏</aside>
        <article>
            网页主体
        </article>
    </section>
    <footer>
        底部
    </footer>
    
</body>
</html>